The present invention relates to an apparatus and a method for monitoring the start of an engine that performs automatic intermittent operation.
A malfunction testing apparatus that detects a malfunction of an engine system only when the running state of the engine satisfies a predetermined condition is known in the art.
One of such apparatuses is a malfunction testing apparatus for a fuel vapor treating system. This testing apparatus detects whether there is a puncture in a vapor passage. The testing is performed in the following manner.
First, the pressure in the vapor passage is lowered below the atmospheric pressure and the passage is then sealed. The rate of pressure increase in the passage is monitored.
If the rate of pressure increase is equal to or greater than a predetermined level, the apparatus determines that there is a malfunction, or a puncture. If the rate of pressure increase is less than the predetermined level, the apparatus judges that there is no malfunction. The judgment is based on the fact that the pressure in the vapor passage increases relatively quickly if atmospheric air flows into the passage through a puncture.
However, when the temperature of fuel is relatively high, the amount of vaporized fuel is increased in the vapor passage, which increases the pressure in the passage. If the malfunction test is performed when the amount of vaporized fuel is relatively great, the apparatus is likely to falsely detect a malfunction. Thus, the apparatus performs the test only if the coolant temperature when the engine is started is relatively low. That is, the apparatus performs the test when determining that the fuel temperature is relatively low and thus there is not much fuel vaporization. Accordingly, there will be less false detections of a malfunction.
In the prior art, whether an engine has started is detected by monitoring the engine speed. That is, the engine is judged to have started when the engine speed reaches a predetermined level. The above test is also performed if the coolant temperature is equal to or lower than a predetermined level when the engine speed is judged to have reached a predetermined level.
Hybrid engine systems and economic running engine systems perform automatic intermittent operation. Judging a start of such engine systems based on the engine speed and the coolant temperature is accompanied by the following disadvantages.
In the intermittent operation, an engine is intermittently stopped and started. When the engine is started after a temporal pause, whether the malfunction test should be performed is determined based on the coolant temperature. As a result, not only the malfunction test is suspended every time the intermittent operation is performed, but also, since the intermittent operation raises the coolant temperature, the condition of the malfunction test is less frequently satisfied, which limits the number of the performance of the test.
Such disadvantages can occur not only during the malfunction test but also during other control procedures that are performed when the engine is being cranked.
Accordingly, it is an objective of the present invention to provide a start monitoring apparatus and a method that prevent control procedures from being suspended by automatic intermittent operations of an engine.
To achieve the foregoing and other objectives and in accordance with the purpose of the present invention, an apparatus for monitoring start of an engine is provided. The engine performs automatic intermittent operation with electricity being supplied to an engine system. The apparatus includes a controller for judging that the engine is started with electricity being supplied to the engine system. After judging that the engine has started, the controller assumes that the engine is running even if the engine is stopped due to automatic intermittent operation until the supply of electricity to the engine system is stopped.
The present invention also provides a method for monitoring start of an engine. The engine performs automatic intermittent operation with electricity being supplied to an engine system. The method includes judging that the engine is started with electricity being supplied to the engine system, and assuming that the engine is running even if the engine is stopped due to automatic intermittent operation once the engine is judged to be started until the supply of electricity to the engine system is stopped.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.